Thread bobbin and method of making



July 5, 1 949.

E. B. NELSON THREAD BOBBIN AND METHOD OF MAKING Filed April 5, 1946 I INVENTOR.

471115 B, NELSON BY j? flZ'TOR/VEK Patented July 5, 1949 UNITED STATES PTENT OFFICE THREAD BOBBIN AND METHOD OF MAKING Emil R. Nelson, East Hampton, Conn., assignor to The Lloyd E. Cone Thread 00., Moodus, Conn, a corporation of Connecticut Application April 5, 1946, Serial No. 659,927

'7 Claims. 1

The invention relates to a bobbin of the type comprising a cylindrical mass of thread wound on a tubular core and supported at its ends by means of discs which are suitably secured to the end portions of the core. A wide variety of bobbins of this general type have been heretofore proposed and used and there are many different means for securing the end discs to the core. In most prior instances the end portions of the core tube have been spun or swaged outwardly to form distinct beads or flanges which project beyond the inner edges of the discs to lock the said discs in place.

The general object of the present invention is to provide a bobbin of the type described and a method of making the bobbin wherein the discs are held in place by the mere radial expansion of the end portions of the core tube so as to forcibly engage the said end portions with discs, Without forming any definite bead or flange at the ends of the tube.

A more specific object of the invention is to provide a bobbin and a method of making the same wherein the tube is formed of a relatively soft material, and wherein the discs are formed of a material which is relatively much harder so that the relatively hard discs will resist the expansion of the tube at the zones of engagement therewith, the tube being expanded at both sides of each zone of engagement so that th discs are seated in self-formed grooves in the tube and are thus firmly held in place.

Other objects of the invention will be apparent from the drawing and from the following speciflcation and claims.

vIn the drawing 1' have shown in detail a preferred form of bobbin embodying the invention and a preferred method of making the bobbin, but it will be understood that various changes may be made in the bobbin and the method as shown, and that the drawing is not to be construed as defining or limiting the scope of the invention, the claims forming a part of this specification being relied upon for that purpose.

Of the drawing,

Fig. 1 is a longitudinal sectional view showing a bobbin at the completion of the initial step of the method.

Fig. 2 is a sectional view showing the bobbin at Fig. 3 is a sectional view showing the bobbin at Fig. 5 is an end view of the completed bobbin.

Fig. 6 is a combined sectional and elevational view showing an apparatus by means of which the second step of the method may be practiced.

Fig. '7 is a combined sectional and elevational view showing an apparatus by means of which the final step of the method may be practiced.

Referring to the drawing, particularly Fig. 1 thereof, It] is a tubular core which may be formed of any suitable material, but which is preferably formed of a relatively soft material such as paper or compressed fiber. Thread is cross-wound on the core H) in any usual or preferred manner to form a centrally apertured cylindrical thread mass i2. The length of the thread mass and the length of the core are preferably substantially the same, but the thread mass may be slightly shorter than the core as shown.

After the thread mass l2 has been formed it is compressed by pressure applied longitudinally so that its length is substantially reduced, as shown in Fig. 2. Preferably, when pressure is applied to the thread mass [2 to reduce the length thereof, pressure is also simultaneously applied to the ends of the tube It) to somewhat reduce the length thereof. The endwise compression of the tube it causes the walls thereof to be slightly increased in thickness, the inner diameter remaining sub stantially the same. Due to the compression the interior and exterior surfaces of the tube may become somewhat irregular, as indicated in Fig. 2, but the interior diameter remains substantially uniform throughout. The tube it is compressed to a much smaller extent than the thread mass 12, the result being that the end portions M, M thereof protrude, as indicated in Fig. 2.

After the thread mass has been compressed, as shown in Fig. 2, two thin centrally apertured discs it, it are assembled with the compressed thread mass 12 and with the protruding end portions It, M of the tube, as shown in Fig. 3. The apertures in the discs l6, it are of such diameter that the inner edges of the discs closely fit the outer surface of the protruding end portions. The discs it, it are of substantially uniform thickness throughout and they are preferably formed of a material much harder than that of the tube ill and the discs may advantageously be formed of a transparent plastic material which enables the thread mass to be conveniently viewed at the ends. .This makes it possible to conveniently observe the color of the thread and also to observe the amount of thread remaining on the bobbin. The discs l8, l8 are preferably very thin, the thickness thereof being substantially exaggeratedin'ths drawing. Each disc ill may have a fiat central portion I8 which is perpendicular to the axis thereof. Each disc I6 also comprises a portion 20 which is outwardly curved in transverse section. The diameter of the end discs IE. it is slightly greater than that of the thread mass, and the inner faces of the discs engage near their periphery with the peripheral corners of the thread mass, as shown.

After the parts have been assembled, as shown in Fig. 3, longitudinal pressure is applied to the ends of the tube II], this pressure serving to further shorten and expand the tube. The walls of the tube are further thickened but the internal diameter remains substantially the same. Due to the fact that the central portion of the tube is surrounded by the compressed thread mass, the said inner portion is expanded to only a very slight extent, if any, but the protruding end portions I 4, I4 are substantially expanded and shortened, asshown in Fig- 4. The expansion of the end portions I4, I4 causes them to firmly grip the discs I6, I6 to hold thediscs in place. .No substantial distortions or changes in shape occur in the discs I6, I6 during the expansion of the tube. Furthermore, in view of the fact that the material of the tube is relatively soft, whereas the material of the discs is relatively hard, the tube can have little or no expansion at its zones of contact with the discs. but it expands at both sides of the said zones ofv contact, the result being that after expansion the inner edge portions of the discs are .seated in self-formed annular grooves near the outerendsof the expanded end portions M, I4.

It will b seen from the foregoingdescription that the discs I6, I6 are firmly secured to the tube without the formation ofany distinct beads or flanges on thetube, and that the discs themselves are notin any. way bentor deformed.- With the discs seated in self-formed grooves, as shown and described, they areflrifnly held even when the bobbin is nearly empty and when they are no longer supported by the thread mass. The grooves not only prevent outward movement of the discs but they also prevent inward movement thereof. Notonly are the discs. held in lace by their engagement in the grooves, but also they are subjected to radially outward pressure which would tend to hold them in place frictionally, even if there were no grooves.

It will be observed thatin the completed bobbin. as shown in Fig. 4, the curved portions 20, 20 of the discs are tangent to planes which are spaced outwardly from the ends oithe'tube, thusmaking it impossible for thread looped. around the bobbin to be caught bythe protruding, portions of the tube.

Fig. 6 shows an apparatuswhich may be used for compressing the thread mass and the tube from the condition as shown in Fig. l to the condition as shown in Fig. 2. As shown, the apparatus comprises an anvil 23 supported in a base 24. The anvil has a centralhole 2.6, the diameter of which is substantially the same, asthe diameter of the hole. inthetube ll'taiidthe said; hole is countersunk, as shownat 2 ,..t0. receive one end portion Id of the tube. .A; plunger 33 is positioned vertically above the anvil 22Iand .is guided for vertical movement in a bearing member 32 suitably supported on the base 2d by means of uprights 34, 3d. The plunger 30 is centrally apertured to receive vertically movable pilot rod 36 and, the aperture 1n1theplunger is. provided witlia countersinkifit to receive the other end I portion I l of thetubei-"The'upiier end-bf the pilot rod 36 is secured to a member lll which is vertically reciprocable by suitable means not shown. A coil spring 152 surrounds the plunger 3!] and tends to hold it in its upper position. Upward and downward movement is limited by means of a screw 44 which enters a slot in the plunger.

In operation the assembly comprising the tube I ii and the thread mas 12, as shown in Fig. 1, is placed on the anvil 22, as shown by dotted lines, and then the member ll] is moved downward. The downward movement of the member 40 first causes the pilot rod 36 to move into and through the tube Ill to support the inner wall of the tube and prevent collapsing. Continued downward movement of the member lll causes it to engage the top of the plunger 30 thus forcing the plunger downward into engagement with the thread mass which is compressed longitudinally to the condition shown in Fig. 2. The depths of the two countersinks 28 and 38 are preferably such that the ends of the tube Ill are engaged just prior to the-completion of the compression of the thread mass so that the tube is compressed and somewhat shortened as shown in Fig. 2.

The apparatus shown in Fig. '7 is very similar to that shown in Fig. 6, the only difference being that a different anvil d6 is substituted for the anvil 22 and a different plunger 48 is substituted for the plunger 30. The top face of the anvil 46 and the bottom face of the plunger 48 are shaped toconform to the shapes of the discs I6, I5, and the, said anvil and the said plunger are formed with very shallow countersinks 5E] and 52 to re solve the end portion i l, I4 of the tube.

The assembly shown in Fig. 3 is placed on the anvil 46, as shown by dotted lines in Fig. '7, and the operation as described in connection with Fig. 6 is repeated. The pilot rod 3Eif1rst moves into and through the tube to support the inner wall thereof and prevent collapsing, and continued downward movement of the member 48 causes the plunger 48 to move downward to engage the assembly. The horizontal faces of the countersinks 5B and 52 engage the ends of the tube I0 causing the end portions I4, l4 thereof to expand and grip the discs I6, I6, as already described in detail in connection with Fig. 4.

It will be understood that Figs. 6 and 7 are intended merely to illustrate simple means for practicing the method of the invention, and that in actual practice more elaborate and complete apparatus would be used. Such complete apparatu would include automatic means for feeding the bobbins from station to station, automatic means for applying the discs thereto, and automatic means for operating the pilot rods and plungers.

What I claim is:

1. In a wound thread bobbin, the combination of a central cylindrical tube of relatively soft material, a cylindrical mass of thread wound upon and supported by the tube and longitudinally compressed with portions of the tube adjacentthe ends thereof protruding beyond the said compressed mass, and two centrally apertured thin circular discs of relatively hard material engaging the ends of the thread mass, the said discs having their inner portions substantially perpendicular to the axis of the. tube and having their inner edges in engagement with the protruding portions of the tube, each end portion of the relatively soft tube beingradially expanded except where expansion. is resisted by the correspending relatively hard disc so as to form a continuous annular groove in which the inner edge of the disc is seated with the sides of the groove engaging the inner and outer faces of the disc.

2. In a wound thread bobbin, the combination of a central cylindrical tube of relatively soft material, a cylindrical mass of thread wound upon and supported by the tube and longitudinally compressed with portions of the tube adjacent the ends thereof protruding beyond the said compressed mass, and two centrally apertured thin circular discs of relatively hard material engaging the ends of the thread mass with their inner edges engaging the protruding portions of the tube, each disc having its extreme inner portion substantially perpendicular to the axis of the tube and spaced inwardly from the corresponding end of the tube and each disc being outwardly curved in transverse section so that a plane tangent to the outermost curvature is spaced outwardly from the corresponding end of the tube, each end portion of the relatively soft tube adjacent the corresponding relatively hard disc being radially expanded except where expansion is resisted by the disc so as to form a continuous annular groove in which the inner edge of the disc is seated with the sides of the groove engagin the inner and outer faces of the perpendicular portion of the disc.

3. The method of making a thread bobbin, which comprises in combination, winding a mass of thread on a tube of relatively soft material having a length substantially the same as that of the mass, compressing the thread mass longitudinally so as to leave the end portions of the tube protruding, assembling with the compressed thread mass and with the protruding end portions of the tube two thin discs of relatively hard material which closely fit the said end portions, and applying longitudinal pressure to the tube to shorten it and to cause the said end portions of the soft tube to expand at both sides of each hard disc so as to form annular grooves in which the discs are seated.

4. The method of making a thread bobbin, which comprises in combination, winding a mass of thread on a tube of relatively soft material having a length substantially the same as that of the mass, compressing the thread mass longitudinally so as to leave the end portions of the tube protruding, assembling with the compressed thread mass and with the protruding end portions of the tube two thin discs of relatively hard material which closely fit the said end portions, and applying longitudinal pressure to the tube to shorten it and to cause the said end portions of the soft tube to expand to a greater extent than the central portion, the expansion of the said end portions taking place at both sides of each hard disc so as to form annular grooves in which the discs are seated.

5. The method of making a thread bobbin, which comprises in combination, winding a mass of thread on a tube having a length substantially the same as that of the mass, compressing the thread mass longitudinally and simultaneously applying longitudinal pressure to the tube to initially shorten it to an extent less than the extent of compression of the thread mass so as to leave the end portions of the tube protruding, assembling with the compressed thread mass and with the protruding end portions of the shortened tube two thin discs which closely fit the said end portions, and again applying longitudinal pressure to the tube to further shorten it and to expand the end portions thereof so as to cause the said end portions to grip the discs and hold them in place.

6. The method of making a thread bobbin, which comprises in combination, winding a mass of thread on a tube of relatively soft material having a length substantially the same as that of the mass, compressing the thread mass longitudinally and simultaneously applying longitudinal pressure to the tube to initially shorten it to an extent less than the extent of compression of the thread mass so as to leave the end portions of the tube protruding, assembling with the compressed thread mass and with the protruding end portions of the shortened tube two thin discs of relatively hard material which closely fit the said end portions, and again applying longitudinal pressure to the tube to further shorten it and to expand the end portions thereof so as to cause the said end portions of the soft tube to grip the hard discs and hold them in place.

7. The method of making a thread bobbin, which comprises in combination, winding a mass of thread on a tube of relatively soft material having a length substantially the same as that of the mass, compressing the thread mass longitudinally and simultaneously applying longitudinal pressure to the tube to initially shorten it to an extent less than the extent of compression of the thread mass so as to leave the end portions of the tube protruding, assembling with the compressed thread mass and with the protruding end portions of the shortened tube two thin discs of relatively hard material which closely fit the said end portions, and again appliyng longitudinal pressure to the tube to further shorten it and to expand the end portions thereof so as to cause the said end portions of the soft tube to expand at both sides of each hard disc as to form annular grooves in which the discs are seated.

EMIL B. NELSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,961,730 Baker June 5, 1934 2,097,305 Robinson Oct. 26, 1937 2,098,218 Baker Nov. 9, 1937 2,203,286 Simpson June 4, 1940 2,3753% Stahl May 8, 1945 

